In current wireless networks, multiple wireless technologies are available to a mobile user. For example, a higher data rate service may be available to the mobile user at the center of a large urban area, but not necessarily available at the edge of the large urban area or in suburban areas. In this case, as the mobile user moves from the center of the large urban area towards the edge or towards the suburban areas, the wireless terminal will require a handoff between different technologies (e.g., 1X wireless systems and 1X-EVDO (evolution data optimized) rev. A wireless systems). Without the handoff, the wireless calls of the wireless terminal will be dropped as the mobile user leaves the higher data rate service coverage area. Dropped calls are a major cause of dissatisfaction for mobile users.
In one example of inter-technologies, 1X wireless systems provide ubiquitous coverage while 1X-EVDO rev. A wireless systems are not yet widely deployed. 1X-EVDO rev. A wireless systems are optimized for widespread packet data coverage at a higher data rate than the baseline 1X wireless systems. Voice over Internet Protocol (VoIP) calls on 1X-EVDO need to be handed off to a 1X wireless system at the edge of the coverage of the 1X-EVDO wireless system. In general, at the edge of the coverage of one technology towards the coverage of another technology, handoff is needed. For example, handoffs are required between Universal Mobile Telecommunications (UMTS) and 1X wireless systems, between wireless Local Area Network (LAN) and 1X wireless systems, and between wireless LAN and Global System for Mobile/Universal Mobile Telecommunications System (GSM/UMTS) systems, etc.